This invention relates to a tape tensioning drive system for tape recorders. More particularly, the invention is suitable for use in a tape tensioning system for use with tape recorders having coaxially mounted reels as used for data recording in applications where minimum size, weight and power is required. The system may also be used with non-coaxially mounted reels.
In such applications, it is necessary for the secure recording and retrieval of data that a constant tape tension be maintained across the recording and reproducing heads. Where coaxially mounted reels are used it is common to utilize negator springs to control the tension in the loop between the takeup and supply reels. However, such springs, because they are flexed, are subject to failure and thus limited in life. The springs require relatively large amounts of space and require different configurations and sizes as the tape lengths change. Furthermore, although the negator spring will supply the force to induce tension in the tape, it will be a function of the reel diameters. In such arrangements, the tape drive capstan motor must overcome the friction in the springs as well as the mass of the reels, thus increasing power requirements. Even with such springs other tensioning subsystems such as hysteresis brakes and tension arms are required at the head area to maintain constant tape tension.
While other techniques are known for controlling tape tension, such as variable pulley drives, such systems also introduce problems of their own which limit their usefulness. Certain systems utilize separate motors for each reel, which obviously results in added cost and complexity. Finally, previous systems using electrical devices to provide tape tension had difficulties when the system was unpowered. The present invention is directed to overcoming these difficulties.
Accordingly it is an object of this invention to provide an improved tape tensioning device for tape recorders.
It is another object of this invention to provide an improved tape tensioning device for tape recorders having coaxially mounted reels.
It is another object of this invention to provide an improved tape tensioning system that can provide varying amounts of torque to the reels.
It is another object of this invention to provide an improved tape tensioning device that is lightweight and compact.
It is a further object of this invention to provide a tape tensioning device that is independent of reel size and drive speed.
It is another object of this invention to provide an improved tape tensioning device that has low power consumption.
It is another object of this invention to provide an improved tape tensioning system using only a single reel drive motor.
It is another object of this invention to provide an improved electrical tape tensioning system that will provide tape tension even when the system is unpowered.
Still further objects of this invention will become apparent upon a reading of the detailed specification to follow.